Potential pollutant used for Tisbury sidewalks



A chemical used to cure sidewalks poured for the Massachusetts Department of Transportation (MassDOT) Beach Road project may be harmful to aquatic environments, yet it was power-washed near harbor-connected storm drains and the curbing that links to them. A safety data sheet for the product states it shouldn’t be allowed to reach sewage systems or “any water course,” and if it does, “respective authorities” should be informed. 

“The product is called TOP-CAST 150,” MassDOT spokesperson Judith Reardon Riley emailed. “This type of treatment, that slows the cure of the top layer of concrete, is an industry standard, and is included in the town’s sidewalk design specifications. We have been in contact with the manufacturer, Dayton Superior, and they advised the product ingredients and the proportions are proprietary, but stated the product contains inert pigments and water-soluble polymers.”

When warnings found on the safety data sheet were pointed out to MassDOT, Reardon Riley wrote, “In adherence with construction best practices, we utilized absorbent pads and silt sacks to prevent the waste material from entering the drainage system. The residual cement paste and sand was cleaned by hand shoveling and mechanically sweeping the roadway gutter upon completion for the power-washing.”

Reardon Riley further wrote, “The material was handled, stored, applied, and removed by the prescribed practices to prevent any accidental discharge of the product during application. Because of these factors, we were not required to notify the respective authorities, as all materials were contained.”

Photographs taken by The Times of recently power-washed sidewalk show water residue pooled along the curb. The photographs show no “absorbent pads and silt sacks” evident near storm drains, along curbing, in the vicinity of areas of bare earth, or anywhere else. 

Tisbury DPW director Kirk Metelll told The Times MassDOT placed silt catchers in the storm drains for the construction period. Metell isn’t sure they filter chemicals, however. He said TOP-CAST 150 wasn’t something Tisbury put in the specs for the sidewalks. He provided a copy of the specs. Metell said while using such a chemical isn’t uncommon in that type of masonry, there are other methods, including just using water, that can achieve the same type of surface. 

Meanwhile, The Times asked about an unpaved section of the sidewalk between Five Corners and Boch Park — an unpaved section that had recently installed curbing in front of it removed to accommodate a driveway. Reardon Riley indicated it was something beyond the original project design. 

“This area was not included in the original design because no curb cut was ever approved or existed at this location,” Reardon Riley emailed. “MassDOT has been in contact with the property owner, and provided technical assistance in applying for a curb cut. This revised application was received after the curbing was placed, but has since been approved, and will be incorporated in this project.”


  1. I just feel so much pride in my environmentally sensitive “green” town, every time I can’t buy a one liter bottle of seltzer water, or get a plastic straw ( not that I personally use straws) but I can refill my reusable # 7 plastic bottle for free at some designated places.
    I am also not able to throw my once used plastic bag out the window of my car where it will eventually get into the ocean and kill a turtle..
    And I am nearly overwhelmed with emotion every time I see one of my town officials driving around in their electric cars.
    Oh the pride I feel living in my “woke” community.

    So who cares if they rip up a few hundred feet of freshly poured sidewalk and spray chemicals that are hazardous to marine life less than 100 ft from the harbor ?
    Who cares if an official lies about their efforts to keep it out of the water. Lying by officials has become the latest trend over the last 5 years. Alternative facts are “in”.
    And why does the Times even print this ? The editor is not a PhD in chemical engineering..
    Just because the manufacturer of the chemical says it’s hazardous doesn’t mean it is. That’s just an opinion…. I bet the person who wrote those specifications was an atheist liberal socialist who hates America.
    Thank God we have the second amendment…

  2. What a great job the town ‘manager’ GRANDE has done, set another environmental disaster in motion with Mr. Metell-on-you. They are second only to the unflappable harbor master and his pump out submarine.

    • Just out of curiosity… why are you putting the blame on town employees when this is on STATE RD ??? A STATE funded project .They have as much say on that project as you do !

    • Hello Anthony
      As I stated in a previous article, my office door is always open. If you have any questions regarding this or any other Tisbury DPW projects please feel free to drop in. My office is located at 115 Highpoint Lane, office hours are 7-4 M-F.

      • Tony does not want things to change.
        He just wants to complain.
        If wanted things to change he would run for public office.
        Or at least take a public service job

    • Anthony– yup, thanks for bringing up that wonderful town official .
      And Darren– As I have been following this manure cart wreck, it seems the town actually does have something to do with it..

      • Hello Mr. Keller
        You are 100% correct the Town/ I has been involved in this project , my role for the past 8 months was simple, I have been given the task to protect the Town’s infrastructure (Sewer and Water Pipes) that resides just a few feet below the the roads surface.
        As Darren correctly stated, this is a Mass.Dot project, all planning,drawings, constructing, funding and managing of this project is under the States control. This project has been on the books for over 10 years , and as you can imagine several changes to the original design have been made and implemented.
        As I have stated several times my office is alway open, feel free to stop.

      • Don, when are you going to fix things by running for office?
        Or is sitting back and complaining more your style?

    • Anthony I’m surprised…. you work for the ship yard…. the town supports the expansion… you live in OB yet you complain like tou pay taxes in Tisbury…. focus on tour own town or get a hobby… your credibility just lost merit….

      • Darrin, I Must really be getting under your skin if you are stalking my place of employment, living on an island makes it one community. Have some happy holiday’s!!!

  3. What does the second amendment have to do with what must be the most expensive sidewalk in the country?
    A moderate Democrat licensed gun owner.

    • Read the comments in the article about the bb gun at Cottle’s. That will explain it. Don is being sarcstic

  4. Can we look at the area for a moment?
    Two gasoline stations.
    Several boatyards.
    Fuel and oil storage/ dealer.

    Perspective please

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